Stephen Amell auditioned years ago to play Booster Gold in Season 10 of Smallville.
In Back To The Future Part 2 after Marty defeats Griff and his gang in 2015, Doc Brown reappears in a change of clothes if you look closely at his shirt there are images of trains all over shirt, a little nod towards the events of Back To The Future Part 3 which speaking of which when Marty and Doc Brown go to hijack the train in 1885 they have there faces covered if look very carful at the cloth covering Doc Browns face it’s the shirt from 2015 with the trains on it.
Pic and deleted scene below from Back To The Future Part 2 shame it was cut the deleted scene isn’t even on blu ray or dvd boxset, another piece of trivia the actor that plays old man Terry is the voice of Roger Rabbit and toy of Roger Rabbit shows at the beginning of the film were Marty looks into the anrique shop along with Marty’s jeans jacket from the first movie.
Also the JVC video camera and tv from the first movie too.
https://youtu.be/xh5L2KdfP2Q
Ray Winstone turned down the role of Hatchet Harry in Lock,Stock and Two Smoking Barrels.Luckily his career wasn't hampered by the decision.
The only real big use of CGI Back To The Future Part 2 was the Hologram Jaws 19 shark in 2015 future part of the movie. Pretty amazing when you back on the film compared to the CGI heavy films of today.
Back To The Future was rejected by over 40 studios including Disney who didn’t like the idea of Marty’s mum falling in love with him lol.
The entire third act of The Predator was totally reshoot
The writer of Se7en,Andrew Kevin Walker has a cameo appearance in the film as a corpse.
Not sure if this has been posted already but the sound of the automatic doors on the U.S.S Enterprise is the sound of toilets flushing on a Russian train.
The character Frank D'Amico in Kick-Ass played by Mark Strong was named as a nod to mobster Anthony "Fat Tony" D'amico from The Simpsons.